| (1) | 39.11 | Lily-Rose Brown | (Herne Hill Harriers) | Chelmsford | 14.08.2022 |
| (2) | 40.02 | Holly Ryan | (Shaftesbury Barnet Harriers) | Kingston | 12.05.2024 |
| (3) | 40.36 | Arabella Wilson | (Winchester & District AC) | Sportcity | 11.07.2021 |
| (4) | 40.39 | Tia Garrard | (Kingston AC & Polytechnic Harriers) | Kingston | 12.05.2024 |
| (5) | 40.8 | Shona Richards | (Epsom & Ewell Harriers) | Wimbledon Park | 21.07.2010 |
| | 40.8 | Maya Bruney | (Blackheath & Bromley Harriers AC) | Bromley | 30.05.2011 |
| (7) | 40.89 | Gracelyn Kendeck | (Croydon Harriers) | Kingston | 18.06.2022 |
| (8) | 40.9 | Alex Shaw | (Guildford & Godalming AC) | Guildford | 30.05.2015 |
| (9) | 41.22 | Rhiannon Gayle | (Croydon Harriers) | Croydon | 18.07.2015 |
| (10) | 41.26 | Lucy Wright | (Herne Hill Harriers) | Chelmsford | 14.08.2022 |
10 athletes with performances of 41.26 or better. |
| Other marks |
